Those are checkpoint files but I would ask support first if removing them is a good idea.  Manual removal of files with Veeam tends to not give the outcome desired and breaks things.

See the checkpoint process here - Background Checkpoint Removal Job - User Guide for Microsoft Hyper-V

Agreed with Chris. If you systemdrive is getting low, did you check your pagefile? Changing the default size of that can take a lot of pain away. 

I’m newer to VEEAM so I unfortunately don’t know if that applies or how to check. I did take a look at the Background Checkpoint Removal Job - User Guide for Microsoft Hyper-V guide but didn’t find what I was looking for. Is it normal to have months worth of logs in this directory?

The logs should clear themselves up automatically but if they are not there could be something else that is not working so a Veeam Support ticket would be best suited for this case.

Gotcha, will do, thanks for the help and info!

Not a problem.  Let us know what you find out and if support provides a solution so others can see what it is that might have the same issue.

Finally got some more motion on this. VEEAM Support recommended on doing a regedit for log files using this KB: https://www.veeam.com/kb1825 it took a while but I got my server operations team to implement the change so hopefully this should resolve my issue. However, VEEAM support did mention any logs outside the retention period I should be able to delete manually.

Great to hear you got a solution and hopefully it works moving forward.